Paris

The only thing to do is to start looking at 2 or 3 small hotels, and do it NOW. To book 12 people into a small hotel you should have started in March or better yet February,

It is late notice for September, but you might consider looking at apartments too. I use vrbo.com and homeaway.com, and there are many other agencies that specialize in apartments in Paris. Apartments can be a real money saver.

I agree you will have to settle for multiple places. September is crowded in Paris due to conventions and trade shows. Take rooms where you can get them!

I rented a three bedroom apartment from www.myparisvisit.com in June of this year. The apartment slept 6 people and had 2 full bathrooms. We really liked this apartment - it was clean and as advertised. We paid 1850 euro for a week which works out to 88 euro per bedroom per night. This agency has many apartments all clustered in the same area of Paris. They might be able to find you apartments fairly close to each other big enough to accomodate everyone in your party.

Have you thought of renting an apartment or a house? I used a company called Paris for Rent. The representative I worked with lives in San Francisco, CA. The entire transaction was in english with US banks. Super easy. An apartment will allow you to save money by having breakfast in the apartment, or dinner if you choose. Worth checking into if you have time. Enjoy yourselves!